As I stated in one of my Travelling Light posts, no gamer actually needs a bucket of dice. Why then do we end up with them?
Disclaimer: I'm not a psychologist or expert on the "gamer mind". I'm just some schmuck with a blog and an opinion.
I think there are several reasons:
FrugalityWe spent good money on the dice, they practically last forever, so why be wasteful and throw them away?
CravingsI like to hangout at my local game store. It's a toy store for my sensibilities. Who goes into a toy store without buying something? However the store either doesn't carry my chosen game system or there isn't anything new published for it, and rarely are there any big item purchases that I want or don't already have. So that leaves me with small item purchases, which for our hobby is either miniatures or dice.
Primary ToolsDice are the primary tool of our hobby. They are essential (unless you are playing Amber). Both GMs and Players use them constantly throughout the game. In fact imho, you aren't a real gamer until you pick and buy your first set of dice. There's a lot of gamer psyche involved with dice: are they lucky, do they look cool, what do they say about my personality? Are these dice going to get me through the next dungeon alive? Dice are to gamers what shoes are to some women.
New ShinyThere are always new styles of dice right around the corner. New colors, new shapes, new materials. Tastes change, and so we pick up the cool new looks and use them until we get bored with them. Then we hear the siren's call of the New Shiny.
Of course I'm basing this off of my own experiences and I am currently hearing the call of New Shiny right now. I love rolling Jumbo dice, I just wish I could get them in the cool color schemes of normal-sized dice. Right now I've got my eye on a set of yellow and orange swirled dice, mainly because they make me think of popsicles.